1. Field of the Invention
The present invention relates to a slurry to be used for chemical mechanical polishing (CMP), a polishing method using the slurry, and a method of manufacturing a semiconductor device wherein the slurry is employed.
2. Description of the Related Art
More increased fineness and more increased integration of elements would be inevitably required in the high performance LSI of the next generation. Furthermore, a multi-layer structure would be also required in the high performance LSI of the next generation. As a result of these requirements, it is now desired, on the occasion of CMP in the planarizing process in the manufacture of a semiconductor device, to suppress the magnitude of local depression (erosion) on the surface to not more than 20 nm in depth.
In the case of the CMP of Cu, since it is required that three kinds of materials such as Cu, Ta and hydrophobic SiOC are concurrently polished, the suppression of erosion is especially difficult. The local depression may generate even when forming embedded insulating film, so that the local depression may become a cause for problems when depositing an organic film such as a resist film on an underlying layer having a trench formed therein. As effective measures for suppressing the erosion, there has been proposed an idea of using a slurry containing a nonionic surfactant having a predetermined range of HLB value. Further, there has been also proposed to employ a slurry where a nonionic surfactant having a specific range of HLB value is employed in combination with an ionic surfactant.
However, even with the employment of these slurries, it is impossible to sufficiently suppress the erosion, so that there are persistent demands for further improvement.
Moreover, there has been also proposed, with a view of minimizing the dishing of Cu film, to employ a metal-polishing composition comprising a composite particle that can be produced from the combined use of polyoxoacid and two or more kinds of nonionic surfactants differing in HLB value from each others. This metal-polishing composition has been actually tried to use in a method of polishing a Cu film at a load of as low as 15 kPa (153 gf/cm2) or less. However, according to this method, since this metal-polishing composition contains no abrasive grain which can contribute to mechanical polishing, it is difficult to secure in-plane uniformity, thus leading to the generation locally of a large magnitude of the dishing of Cu film.